Adds support for taint tolerations for scheduled runs. Useful for
selectively tolerating taints on dedicated node pools.
The new `KUBERNETES_SCHEDULED_RUN_TOLERATIONS` env variable accepts a
comma-separated list in the format key=value:effect (or key:effect for
the Exists operator).
Drive-by: renames all `KUBERNETES_SCHEDULE_*` affinity env vars to
KUBERNETES_SCHEDULED_RUN_* for clarity — this feature isn't used in
production yet or published in a tagged image; the name change is fine.
Saadi Myftija
7210bdee9b